14-11-2012, 01:48 PM
Usage of Industrial Waste Products in Village Road Construction
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Abstract
Now-a-days disposal of different wastes produced
from different Industries is a great problem. These materials
pose environmental pollution in the nearby locality because
many of them are non-biodegradable. In recent years,
applications of industrial wastes have been considered in road
construction with great interest in many industrialised and
developing countries. The use of these materials in road
making is based on technical, economic, and ecological criteria.
India has a large network of industries located in different
parts of the country and many more are planned for the near
future. Several million metric tons industrial wastes are
produced in these establishments. If these materials can be
suitably utilised in highway construction, the pollution and
disposal problems may be partly reduced. Keeping in mind the
need for bulk use of these solid wastes in India, it was thought
expedient to test these materials and to develop specifications
to enhance the use of these industrial wastes in road making, in
which higher economic returns may be possible. The possible
use of these materials should be developed for construction of
low-volume roads in different parts of our country. A review of
various Industrial wastes for use in the construction of
highway has been discussed in this paper. The waste materials
are fly ash, blast furnace slag, cement kiln dust
phosphogypsum, waste plastic bags, foundry sand and colliery
sand , which are the industrial wastes posing problems in
the disposal and being deposited near the industries in India.
INTRODUCTION
Now-a-days disposal of different wastes produced from
different Industries is a great problem. These materials pose
environmental pollution in the nearby locality because many
of them are non-biodegradable. In recent years, applications
of industrial wastes have been considered in road
construction with great interest in many industrialised and
developing countries. The use of these materials in road
making is based on technical, economic, and ecological
criteria. The lack of traditional road materials and the
protection of the environment make it imperative to
investigate the possible use of these materials carefully.
India has a large network of industries located in different
parts of the country and many more are planned for the near
future. Several million metric tons industrial wastes are
produced in these establishments.
BLAST FURNACE SLAG
Blast furnace slag is generated during the melting process
in steel making operations. The slag is a fairly complex
mass that is relatively inert. It is composed of metal oxides
(produced as a result of the oxidation of the metal during the
melting process), melted refractory, sand from recycled
scrap castings, coke ash, and other materials. The physical
form of the slag largely depends on the method of collection.
Slag that is quenched in water will typically form gravel
sized particles. Slag that is removed from the furnace and
poured into sand moulds or “pigs” will typically resemble
boulder sized masses. This type of slag is generally in the
shape of a flat piece of metal and/or small rock sized chunks.
Blast furnace slag has been beneficially used in a number
of applications. The most significant factor that determines
whether or not blast furnace slag is suitable for use is the
particle size. Most of the blast furnace slag that has been
used has either been generated as part of a wet quenching
collection system, or if collected dry, has undergone some
particle size reduction.
CEMENT KILN DUST
Cement kiln dust (CKD) is the finely divided dry alkaline
particulate matter carried from a cement kiln by the exhaust
gas, and captured by the kiln’s air pollution control system.
In general, however, the composition of cement kiln dust is
similar to that of cement and consists of calcium carbonate,
calcite, silicate, potassium sulphate, calcium sulphate,
aluminium oxide, iron oxide, potassium chloride,
magnesium oxide, sodium sulphate, and potassium fluoride.
Cement kiln dust has a chemical composition similar to that
of cement; therefore, the primary value of cement kiln dust
is its cementitious properties. Its alkalinity and particle size
also provide value for a variety of beneficial use options.
PHOSPHOGYPSUM
In fertilizer industries the Phosphate rock, is processed to
make phosphoric acid, contains about 70 percent calcium
phosphate, also contain a large number of impurities, such
as calcium fluoride, chlorides, chromium, and many other
compounds. In the wet process the phosphate rock is treated
with sulfuric acid to produce the phosphoric acid which is
the finished product in the fertilizer. The by-product
remaining after the acid conversion is largely calcium
sulfate and has been given the name phosphogypsum.
Phosphate production generates huge amounts of wastes.
The production of each ton of phosphoric acid is
accompanied by the production of 4½ tons of
phosphogypsum. The phosphogypsum is stored in open-air
storage areas known as stacks. The stacks form as the slurry
containing the by-product phosphogypsum is pumped onto a
disposal site. Over time the solids in the slurry build up and
a stack forms. The stacks are generally built on unused or
mined out land on the processing site. The surface area
covered by stacks ranges from about 5 to 740 acres. The
height ranges from about 10 to 200 feet.
Phosphogypsum is reused for highway construction
aggregate (crushed base and crushed aggregate for asphalt).
CONCLUSIONS
A review of various Industrial wastes for use in the
construction of highway has been discussed in this paper.
The waste materials are fly ash, blast furnace slag, cement
kiln dust and phosphogypsum which are the industrial
wastes posing problems in the disposal and being deposited
near the industries in the state of Orissa.